package apiday03.map;

import java.util.HashMap;
import java.util.Map;

public class MapDemo1 {
    public static void main(String[] args) {
        Map<String,Integer> map = new HashMap<>();
        map.put("语文",99);
        map.put("数学",95);
        map.put("物理",85);
        map.put("政治",88);
        map.put("英语",68);
        System.out.println(map);

        Integer value = map.put("物理",90);
        System.out.println(value);//85
        System.out.println(map);
        value = map.put("地理",75);
        System.out.println(value);//null
        System.out.println(map);
    }
}
